The present invention relates generally to vehicle navigation systems and more particularly to a vehicle navigation system which also determines the condition of roads on which the vehicle navigation system travels.
Maintaining roads in a large metropolitan area can be difficult. In particular, with large road networks, assessing and locating problem areas can be time consuming. Even potholes which are large enough to require immediate attention must first be identified and located. Motorists who report problem road conditions are generally unable to give accurate descriptions of the location of the problem.
The present invention takes advantage of the fact that vehicle navigation systems already include the hardware necessary for mapping problem road conditions traveled by the vehicle navigation system. The vehicle navigation system of the present invention includes at least one inertial sensor, such as an accelerometer, which is used both for propagating the position of the vehicle relative to a map database and for determining the condition of the road.
Poor road conditions, such as a pothole, induce motion signals in the inertial sensors which are normally filtered out for purposes of propagating the position of the vehicle; however, by identifying these signals, the occurrence of a problem road condition can be identified. When a problem road condition is identified, the vehicle navigation system notes the current road, current position of the vehicle, vehicle speed, date/time and associates this data with the identified road condition. Subsequent problem road conditions are stored similarly.
Later, the stored database of problem road conditions can be downloaded and analyzed to determine the location of problem road conditions relative to the map database. Road repair personnel can travel straight to the problem road condition locations based upon the data stored by the vehicle navigation system.